This invention relates generally to the telephony art, and more particularly to an improved system and apparatus for automated testing of trunks and individual subscriber lines. Devices of this general type are known in the art, and the invention lies in specific constructional details which permit improved and extended testing functions providing major reduction in subscriber loop maintenance and repair operating costs.
With increasing trends to subscriber ownership of subscriber equipment, subscriber line testing has acquired an aspect which heretofore has been of relatively little importance. Whereas traditionally subscriber line maintenance has included the maintenance of on site equipment, the trend now is to maintain the subscriber line up to a demarcation point, normally the point of entry to the subscriber location. Thus, in separate subscriber line testing, it is not sufficient to determine a fault on the line. Also required is information relative to the location of the fault, and a determination of whether this location lies within the area of telephone operating company responsibility. Further, the amount and type of equipment to be tested has changed dramatically, along with the types of testing required. Prior art testing systems only partially fill these requirements.
In U.S. Pat. No. 3,969,594, granted July 13, 1976, to Paul V. De Luca, et al., and assigned to the same assignee as the present application, there is disclosed a testing system and apparatus which employs a central processor for accessing subscriber cable pairs via one of a plurality of interface circuits, a trunk selection matrix, a test or no test trunk, located at the subscriber central office. Subscriber lines are seized in accordance with manually or automatically entered information via system input terminals, and an operative code forming part of the request command determines one of several available operating modes. Digital computor apparatus is employed both for data processing and assembling purposes as well as for circuit control. The apparatus also includes a dedicated microprocessor with auxiliary instructions (ROM) and read-write (RAM) memories.
While the above described apparatus possesses a high degree of utility, and has received substantial acceptance, it is not capable of performing the types of tests which not only determine the nature of the fault, but its location as well to the degree necessary for present day subscriber owned equipment.